This is the 2329th most frequent Russian word.
многодетных
"Многодетных" means "of large families" or "having many children."
The word 'многодетных' is used as an adjective describing families that have multiple children, emphasizing their characteristic.
В городе построили новый район для многодетных семей.
A new neighborhood was built in the city for families with many children.
Here, 'многодетных' modifies the implied noun 'семей' and denotes a group qualifying for these benefits.
Пособия для многодетных продолжают увеличиваться каждый год.
Benefits for families with many children continue to increase every year.
In this context, 'многодетных' is used substantively to refer to people or families with multiple children as the subject of discussion.